The arrival of Declan Ganley on to the Irish political scene has unnerved and terrified the ruling elite in both Ireland and Europe. No one predicted it and no one could have foretold quite the impact it would have.

Last June, Ireland held a vote on the Lisbon Treaty, the latest legal document of the European Union to be put before the Irish people by way of a constitutional referendum.

Lisbon was, of course, the successor to the ill-fated Constitutional Treaty, shot down in flames by the voters of France and Holland. Rather than accept defeat, however, EU leaders dressed up the treaty in new clothes, calling it the Lisbon Treaty and then conning their electorates into thinking that it wasn't really the same thing at all and therefore didn't need to be put before them again.

Ireland was always going to be a potential fly in this particular ointment. Thanks to the Irish Constitution - a wonderful document - any ceding of sovereignty from the nation-state to a supranational body like the EU has first to be approved by the people.

Thus was the scene set for the Lisbon Treaty vote of last summer. It was one the political establishment was almost sure to win, especially after Bertie Ahern, damaged by revelations about his personal finances, had been replaced as Taoiseach by Brian Cowen, his gruff Finance Minister.

They did not reckon on Declan Ganley entering the fray. No one did. His entry, and subsequent success, provides an object lesson in how someone with no apparent political base, no grassroots organisation and a message still in gestation, but who happens to be in the right place at the right time, can defeat a deeply entrenched political establishment.

Ganley is a 40-year-old businessman who spent the first years of his life in London - he has an English accent - before returning with his Irish parents to their Galway home. He is what a previous generation might have called a buccaneer. Almost as soon as the Iron Curtain fell he was off to Eastern Europe, where he began to amass his fortune. Exactly how he made his money is still mysterious to outsiders because he is a serial entrepreneur who did not take over the helm of an existing business, or establish just one business and then guide its growth.

This allows his critics to associate him with some of the shadier elements of Eastern European business and politics, something they have not been slow to do. Last year, a current affairs show on the Irish national broadcaster, RTE, even managed to associate him indirectly with what some have described as a mysterious death in Albania, a dreadful smear that caused him to begin libel proceedings against the station.

The vehicle Ganley used to fight the Lisbon campaign was Libertas. He had founded it some months before the campaign as a small pro-free-market think-tank that verged on libertarian in outlook. It wanted a Europe that was open, accountable, properly democratic and more pro-business. It wasn't set up with the Lisbon campaign in mind, but when it began it was tailor-made for Libertas to make its mark. It did this through a well-funded billboard advertising campaign and a relentless whistle-stop tour by Ganley combined with endless media appearances.

The fact that he was new helped him gain profile. The media were tired of the same old faces on both sides campaigning for or against the latest treaty. Ganley was personable and telegenic. He was rich, and even better, he looked rich, always dressing in very sharp pin-stripes.

His London, slightly cockney accent made him somewhat exotic (as odd as that may seem to British readers), and the fact that he had appeared seemingly from nowhere, having made his money - the question still remains how much - in a manner no one seemed able to quite explain, only added to the air of mystery and therefore the media appeal. To some he was a kind of Bond villain, set only on doing evil.

No doubt the endlessly energetic, self-confident Ganley could hardly believe his luck. He had no idea whether his campaign would get off the ground at all and when it went stratospheric it seemed to defy all logic. The main political parties, initially sleepy and taken up mainly with scoring points off one another, grew more and more incensed as Ganley very visibly began to make ground on them. That establishment pillar, the Irish Times, become apoplectic. Its rage at this interloper knew no bounds. Late in the campaign, when it became apparent that the "Yes" campaign could lose, it declared the Irish people mad.

When Lisbon was rejected by a margin of six per cent the shock-waves spread out across Europe. Eurosceptics, whether mild or militant, were delighted. The political class was outraged. Brian Cowen, the new Taoiseach, had been humiliated by his own people and in front of his political peer group across Europe. Ireland, with its tiny population of 4.2 million people, was accused of defying the will, nay the destiny, of an entire continent. In fact, it was merely defying the will of Europe's ruling class. Had Lisbon been put to the vote again in France and Holland, not to mention Britain, it would doubtless have been defeated in those countries as well. Ireland's vote was a proxy vote on behalf of the hundreds of millions of disenfranchised voters across the continent.

It would be an exaggeration to say that Declan Ganley single-handedly defeated the Lisbon Treaty. Fringe groups of the Left and the Right played their part and so did voter anger at politicians. But Ganley received most of the credit, and the blame. It catapulted him to a sort of stardom not just in Ireland but in much of the EU as well. This is exactly what he wanted because all along his aim appears to have been to make Libertas a force in Europe, and his part in defeating Lisbon gave him the equivalent of years' worth of painstakingly building a political movement from scratch.

He has been extraordinarily busy since the defeat of the Lisbon Treaty, dividing his time between his business in America and his nascent party, the first pan-European party since the foundation of the EU. He has addressed meeting after meeting of groups and organisations that are almost consistently on the right of the political spectrum, for example, the Margaret Thatcher Centre for Freedom at the Heritage Foundation in Washington, DC.

He is attracting the support, or at least the interest of, eurosceptics, free-market liberals, social conservatives and Catholics (Ganley is an unabashed orthodox Catholic) and libertarians.

Ganley, mind you, has always rejected the eurosceptic tag, insisting instead that Libertas is pro-Europe and that it is, in fact, "for the ongoing development and integration of Europe".

What this means in practice, he says, is a more powerful parliament that would "have the power to initiate legislation". In addition, the EU would have a directly elected president, but only so long as this had first been approved by the citizens of the EU member-states. At the same time, he states, the EU must respect the principle of subsidiarity and resist "competence creep", which he describes as "competence grab". He told Standpoint: "We want the EU to abide by its own rules and that means not straying outside the competences granted to it. It means abiding by the principle of subsidiarity, which respects the sovereignty of the member-states. If the EU followed its own rules there would be much less euro-scepticism. We will insist that it does."

As an example of competence creep, he noted that the European Court of Justice was already acting as though the Charter of Fundamental Rights were part of EU law. Also, he cited an aborted attempt by the European Commission last year to restrict the right of religious schools to employ only people who they believe would respect their ethos. The Commission said this violated EU equality law. It withdrew its action only under considerable pressure from the affected member-states.

With regard to hot-button social issues such as abortion and same-sex marriage, he says Libertas believes that these should be left exclusively to member-states and that EU competence in such areas as non-discrimination should not be used, as is currently the case, to interfere in family law, over which the EU has no direct competence. Libertas will also do more to highlight corruption and waste within the EU, he insists.

The short-term aim of Libertas is to run candidates in next summer's election for the European Parliament. A total of 785 seats will be up for grabs. Ganley is hoping to raise €75 million (about £70 million) for the campaign and says he has support so far in Poland, Britain, the Czech Republic, Austria, Sweden, France and Holland. Ganley himself may stand in Ireland North West, which includes his native Galway.

He has set himself a daunting task but it is clear that Europe's ruling elites, as well as Ireland's, feel deeply threatened by him. Their attacks are a sign of their insecurity and extreme intolerance of anyone and anything that comes from outside the very narrow and all-too-cosy consensus of EU politics. They are reacting as a cartel would when an interloper threatens their power. For example, ever since the appearance of Libertas, critics, led by the Irish Times, have incessantly been asking about the source of its funding. Funding to political organisations is now so strict in Ireland that it locks in the advantage of the established parties - the cartel - and enhances the influence of the media because it becomes harder than ever to bypass them by spending money to reach voters directly.

Ganley admits to loaning Libertas €200,000 out of the €1 million or so it spent in the Lisbon campaign. No other organisation has had its funding questioned anything like as zealously.

There is also a rule during referendum campaigns in Ireland that both sides in the debate must be given equal broadcasting time. This, again, is thanks to the Irish Constitution. Politicians are examining ways to undermine this requirement.

In addition, every effort is being made to demonise Ganley. There was the aforementioned documentary on RTE. German TV has also attacked him. He has been accused of having CIA links by such luminaries as MEP Daniel Cohn-Bendit, aka "Danny the Red" of 1968 fame. He has been called a "neocon", which is, of course, the functional equivalent these days of calling someone a Nazi.

The president of the European Parliament, Hans-Gert Pottering, wants an investigation into "reports" that Ganley has the backing of those wicked American neocons. This could damage his business interests as well as his political credibility.

The Lisbon Treaty will be back before the Irish people by next October. Europe never takes "No" for an answer. Ganley, therefore, must be reduced to ash and dust before then.

What becomes of Declan Ganley remains to be seen. Perhaps he will continue to defy the odds. Perhaps he and Libertas will do well in the coming elections and become a permanent feature on the political landscape with their insistence that the EU play by its own rules and that it become more democratically accountable. Or perhaps he will fade back into obscurity.

No matter what happens, however, he will have taught us two very important lessons. The first is that a newcomer with good timing and plenty of energy can still challenge the status quo. The second is that the EU treats its dissidents far more ruthlessly than a democratic enterprise should.